Hydrodynamic coupling



June 30, 1970 TETSUYA IIJIMA 3,

HYDRODYNAMIC COUPLING Filed Dec. 5, 1968 4 Sheets-Sheet l June 1 970 TETSUYA llJlMA 3,

HYDRODYNAMIC COUPLING Filed Dec. 5, 1968 .4 Sheets-Sheet IO i June 1970 TETSUYA IIJIMA 3,

HYDRODYNAMIC COUPLING ,4 Sheets-Sheet 5 Filed Dec. 5, 1968 June 30, 1970 TETSUYA IIJIMA HYDRODYNAMIC COUPLING .4 Sheets-Sheet 4 Filed Dec. 5, 1968 United States Patent 3,518,026 HYDRODYNAMIC COUPLING Tetsuya Iijima, Tokyo, Japan, assignor to Nissan Jidosha Kabushiki Kaisha, Kanagawa-ku', Yokohama, Japan Filed Dec. 5, 1968, Ser. No. 781,322 Claims priority, application Japan, Dec. 20, 1967, 42/ 81,430 Int. Cl. F04d 29/18 US. Cl. 416-197 1 Claim ABSTRACT OF THE DISCLOSURE A fabricated hydrodynamic coupling device, in which each vane is connected by tabs to slots of an impeller outer shell and a radially innermost series of slots of the impeller is radially outwardly narrow wedge shaped to clamp the inserted tabs.

The present invention relates to hydrodynamic coupling devices and, more particularly, to fabricated vaned elements of such device.

Fabricated hydrodynamic coupling devices have been proposed wherein the vaned impeller and turbine elements each comprises a substantially semi-toroidal shell, a plurality of semi-circular vanes received within the shell and having tabs received within slots in the shell and a semi-toroidal core having slots receiving tabs on the opposite side of the vanes, these component parts of the vaned element being formed of sheet metal stampings.

One of the known devices comprises an annular retainer plate connected to the inner periphery of the shell and engaging the radially inner ends of the vanes to maintain the tabs in the vanes within the slots in the shell. However, use of a retainer plate is limited to vanes having sufiicient length to have their radially inner ends engage the slots in the retainer plate. Also, an additional fabricating process is necessary to attach the retainer plate to the vanes.

Another known device comprises a specially formed slot in the shell element as the radially innermost slot to receive a corresponding tab of the wane. However, the vanes must be flexed to assemble the vane, and a very accurate forming process is necessary to both vane forming and slot forming. To avoid the inaccuracy, another device punches the portion of the shell adjacent the tab after assembly to deform the material of the shell and to secure the tab of the vane to the shell. However, the punching process is complex and the use of such a process makes it difficult to attain the desired uniform retaining result.

It is an object of the present invention to provide a fabricated hydrodynamic coupling device formed of sheet metal stampings and having a. simpler construction, made by a simpler assembly process, and more economically produced than known devices.

Another object of the present invention is to provide an improved coupling wheel element in which the securing or positioning of the element between the blades and shell is accomplished only by tabs and slots, and only after the blades are assembled to the shell and the core and the tabs are rolled down, are the wheel element components connected firmly without mechanical freedom.

A further object of the present invention is to provide such a wheel element which can be assembled without deformation of the blades, thereby eliminating any adverse effect on the hydrodynamic characteristic of the wheel element.

3,518,026. Patented June 30, 1970 ice A still further object of the present invention is to provide such a wheel element which has a minimum number of parts, simple construction, light weight, and longer life of slot forming punching tool.

Still another object of the present invention is to provide such a wheel element which can be assembled easily without clearance between tabs and slots, and without causing vibration or rattling in operation throughout a long service life.

Briefly stated, one of the important features of the present invention in attaining the above mentioned objects is that, at least radially innermost series of slot of the shell of the vaned element providing radially inward width which is narrower than radially outward width thereof, and the radially inward width being equal or slightly smaller than thickness of the tab of the blade to be inserted and the radially outward width being larger than the tab, and the slot being deformed by inserting the tab and retaining the tab by elastic engagement of the sides of the slot.

For the purpose of describing more particularly a preferred embodiment of the invention, reference will be made to the accompanying drawing, in which:

FIG. 1 shows a longitudinal sectional view of a portion of a hydraulic torque converter according to the invention;

FIG. 2 shows a longitudinal sectional view of a pump wheel shown in FIG. 1;

FIG. 3 shows a partial end view of the pump wheel shown in FIG. 2;

FIG. 4 shows a sectional view of the pump outer shell of the pump wheel shown in FIG. 3 along line 44 of FIG. 5;

FIG. 5 shows a partial end view of the pump outer shell shown in FIG. 4;

FIG. 6 shows enlarged partial sectional view along line 66 of FIG. 2; and

FIG. 7 shows enlarged view of slot along line 77 of FIG. 4.

Referring to the drawing, more especially to FIG. 1, 1 designates a torque converter assembly. The torque converter assembly 1 shown in FIG. 1 is a three element assembly consisting of a pump 2, a turbine 3 and a stator 4. However, the present invention can be applied to any hydrodynamic coupling device and the drawing shows only one preferred embodiment. The torque converter assembly 1 is utilized to transmit and convert torque by momentum change of fluid therein by means of the pump, the turbine and the stator. The main portion of the torque converter assembly 1 is included in a vessel formed by a pump outer shell 5 and a cover 6 which secures a pilot boss 7 supported by a pilot bearing 8 which is secured to a crankshaft 9 of the engine. The other end of the torque converter provides a sleeve shaft 10 which is secured to the outer shell 5 and is supported by a bearing 11 which is secured to a casing 12.

The pump 2 comprises an outer shell 5, an inner core 13 and blades 14 to form spaces between the shell 5 and the core 13 forming a portion of power fluid circulation path and the blades 14 are inserted substantially radially to define the spaces. The outer shell 5, the core 13 and the blades 14 are all fabricated from suitable metal sheet and assembled as to be explained in more detail hereinafter.

The turbine 3 comprises: an outer shell 15 and an inner core 16 forming a fluid circulation path, and blades 17 which are inserted substantially radially between the shell 15 and the core 16. The outer shell 15 is secured to a turbine hub 18 which in turn is spline connected to an outer shaft 19.

The stator 4 comprises: a ring 20 and a hub 21 defining a fluid path, and a plurality of radially disposed blades 22 to form an axial flow wheel. The stator 4 is supported through a one-way brake 23 on a fixed shaft 24 which is secured to the casing 12. The one-way brake 23 is disposed between an outer race 25 which is secured to the hub 21 and an inner race 26 which is spline connected to the shaft 24 to allow rotation of the stator 4 only in the direction of rotation of the engine.

To the outer surface of the cover 6, a plurality of bosses 27 are secured, such as by welding, to receive bolts 28 securing a drive plate 29 which is secured to the engine crankshaft 9 by means of bolts 39. The engine torque is transmitted through the crankshaft 9, the drive plate 29, bosses 27, and cover 6, to the pump outer shell 5. A portion of the torque is transmitted through the sleeve shaft 10 to an oil pump 31 to supply torque converter fluid, and a major portion of the torque is transmitted through the pump 2, the hydraulic fluid, and the turbine 3 to the output shaft 19. The stator 4 furnishes the reaction torque through the casing 12 to change the flow direction of the fluid and increase the momentum of the fluid, thereby causing a multiplication of the turbine output torque in a manner well-known in the art.

The pump 2 is shown in detail in FIGS. 2 and 3. The pump outer shell is made from sheet metal to provide a semi-toroidal depression and radially spaced sets of circumferentially spaced slots 32, 33 and 34 as shown in FIGS. 4 and 5. Each blade 14 is also made from sheet metal and has a semi-circular outer edge to fit within the semi-toroidal surface of the outer shell 5. Each of the blades 14 is provided with three tabs 35, 36 and 37 extending radially outward of the semi-circular margin of the blade, and fitting into the corresponding slots 32, 33 and 34 respectively. The alignment of the slots follows the line of contact between the outer shell 5 and the blade 14 so that no deformation of the blade is necessary to assemble the blades to the shell. The inner edge portion of the blade 14 is formed with a semi-circular recess to receive the inner core 13 and is provided with two tabs 38 and 39.

The inner core 13 is also made from sheet metal to form a semi-toroidal outer surface to engage the inner edge of the blades 14 and is provided with two rows of slots 40 and 41 to receive the tabs 38 and 39. As shown in FIG. 6, the tabs 38 and 39 are inserted in the slots 40 and 41 and folded or rolled down flat against the inner curved surface of the core 13 to lock the inner core 13 to the blades 14 and also to lock the whole pump assembly 2 as will be described in more detail hereinafter.

FIG. 7 shows an enlarged view of one of the slots 34 according to the present invention, as seen along line 77 in FIG. 4. The solid line shows the slot 34 and dash-and-dot line shows tab 37 of the blade 14 which is to be inserted in the slot 34. As shown in FIG. 7, the radially inward width Bi of the slot 34 is smaller than the radially outward width B0 thereof. The inward width Bi is equal to or slightly smaller than the width of the tab 37 and the outward width B0 is slightly larger than the width of the tab 37. As mentioned above, when the blades 14 are assembled to the shell 5, the tabs are inserted sequentially from outside to inside ones of slots 32, 33 and 34, so that tab 37, for example, is inserted into the slot 34 from the wider outward portion to the narrow inward portion of the slot 34. Thus, by wedge action of the tab 37, the sides of the slot at the narrow portion are easily elastically deformed by the insertion of the tab, and retain the tab by elastic engagement to prevent rattling or displacement of the blade 14.

With impeller wheel 2, according to the present invention, no retainer means are provided to connect the blades to the shell without mechanical freedom, and, only after the blades are assembled to the shell, the core assembled to the blades, and the tabs of the blade rolled flat to the surface of the core, is the whole assembly connected without mechanical freedom. The inserted blade may be removed forcibly by rotating the blade about the radially outer slot 32. However, when the blade is pulled parallel to the axis of the pump 2, the blade 14 is retained by engagement of the edge surface 32a of the slot 32 and the edge surface 35a of the tab 35, as the surfaces 32a and 35a are substantially perpendicular to the axis of rotation in the assembled position.

By providing the wedge shaped slots 34 with a radially outward width which is slightly larger than the width of the blades 14, according to the present invention, assembly of the blades is very easily performed. As mentioned above, to assemble the blades 14 to the shell 5, the edge portion 35b of tab 35 is first inserted into the corresponding radially outermost edge portion 32b of the slot 32, and the blade is rotated about the point 35b to sequentially insert the tabs 35, 36 and 37 to the slots 32, 33 and 34. Thus, each tab is first inserted in the radially outward portion of the slot which is broader than the blade and then moved to the radially inward narrower portion, so that the assembly operation is easily performed. As the narrower sides of each slot engage elastically the respective tab of a blade without any clearance, no further means such as punching, staking or retainer are necessary and the blades are retained in the shell without any rattling or vibration. Further, the service life of a punch to form slots 34 in the shell 5 is considerably lengthened compared to parallel sided slots.

The primary object of the present invention is to provide a positive assembly without clearance between shell 5 and blades 14 of the pump 2. However, the wedge shaped slots according to the present invention may have other applications to the turbine 6, in which one or more rows of slots, such as slots 47 shown in FIG. 1, is made to provide radially outwardly widened sides, so that by suitably selecting the widths of the wedge, tabs 43 of the blades 17 are positively engaged in the slots '42 without any clearance, thus considerably simplifying the rolling or caulking process.

It will be appreciated that the vaned elements of a torque converter or fluid coupling according to the invention are formed of minimum numbers of sheet metal stampings, can be assembled by a simple process, clamping or radially inward edge portion of the blade is sufiicient, vibration or rattling is prevented, and is light weight and suitable to mass production, compared to known fabricated vaned elements. Further, assembly is easier as deformation of the blade is not necessary, and fluid flow channels are maintained with accurate hydrodynamic dimensions. Also, the service life of the slot forming punching tool is longer.

What is claimed is:

1. In a vaned element of a hydrodynamic coupling including a hollow sheet metal shell having a generally semi-toroidal surface provided with at least three series of slots each at circumferentially spaced locations on the interior surface of said shell including a first series of slots on the radially outermost locations and a second series of slots on the radially innermost locations, the slots of each series being arranged in spaced circumferential relationship about the axis of said shell, a hollow semi-toroidal sheet metal core being provided with at least two series of slots each at circumferentially spaced locations piercing through said core, and a plurality of sheet metal blades with an outer arcuate margin and an inner arcuate margin that correspond in shape to the toroidal shape of said interior surface of the shell and outer surface of the core respectively and tabs corresponding to said slots of the shell and the core, improvements comprising, said slots of the shell corresponding to each said blade being arranged to substantially align the longitudinal edges of the slots to predetermined fluid flow lines formed by the assembled blade to enable inserting the tabs of the blade without flexing the blade, the radially outermost marginal surface of each slot of said first series of slots being substantially perpendicular to the rotation axis of said shell, the edge surface of said tab engaging said surface of said slot being also substantially perpendicular to said rotation axis, each slot of at least said second series of slots having a radially inward width which is narrower than the radially outward width thereof, said radially outward width being larger than the thickness of the blade to be inserted, said radially inward width being equal to or less than the thickness of the blade and being forcibly engaged to the inserted tab of the blade by assembly of the blade, clamping or positioning elements between the shell and the blades being only said slots and tabs, and said shell, blades and core being assembled into mechanically clamped relation only after the tabs are bent against the inner surface of the core.

References Cited UNITED STATES PATENTS 2,357,295 9/ 1944 Thompson.

2,692,561 10/ 1954 Zeidler.

2,692,562 10/ 1954 Zeidler.

2,701,531 2/1955 English.

2,779,292 1/ 1957 Zeidler.

3,316,622 5/1967 Jandasek 60-54 XR FOREIGN PATENTS 684,3 85 12/ 1952 Great Britain.

EDGAR W. GEOGHEGAN, Primary Examiner US. Cl. X.R. 

